Impulse noise on telephone lines, which results in clicks in customers' receivers, is generated when switching connections are opened and closed. Varistors connected across the tip and ring conductors in customer telephone sets limit this noise to a level which will not injure the ear. During call set up, such limited click noise is not annoying to the customer because he expects it and it indicates that the switching system is responding to his request. However, where there is a reswitching of connections, as is common in several of the newer switching services, noise of the same level occurs during the talking connection and, since unexpected, is distracting and annoying to the customer.